Applications utilizing a 12 H.P. or larger D.C. motor that demand frequent starting, stopping, reversing, and speed regulation require______________?
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Answer: A. drum type controller is used
Explanation
Drum type controllers feature robust mechanical switches engineered to handle heavy electrical arcs safely. Large motors drawing substantial currents require durable switching hardware for frequent starting and reversing operations. These controllers integrate multiple contact points to manage complex resistance staging for large power ratings. Motors rated at twelve horsepower and above generate significant electrical and mechanical stresses during switching. Manual drum switches allow operators to cycle motor states repeatedly without premature contact degradation. Arc extinguishing barriers inside drum controllers prevent dangerous electrical flashovers during rapid reversals.
Heavy industrial cranes and hoists utilize drum controllers for precise, frequent maneuvering of massive loads. Manufacturing plants rely on rugged controllers to withstand the rigors of continuous reversing production lines. Proper controller selection minimizes electrical maintenance downtime in demanding high-power industrial environments. Three-point starters are generally limited to fractional and moderate horsepower shunt motors rather than heavy machinery. Four-point starters provide adjustable no-volt release circuits but lack the heavy-duty switching architecture for frequent reversing. Stating all above can be used ignores the specific current ratings and mechanical limitations of standard starters.
- Subject
- Engineering
- Category
- Electrical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
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Answer: A. reducing the field current
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Answer: D. Cumulative compound motor
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Answer: D. Rate of flow of ventilating air
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Q6. Plugging operation provides the____________?
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